Schwelsig War

The Schwelsig War (1837–1839) was a conflict that Prussia and Mecklenburg started over the region of Schwelsig-Holstein in Denmark. The conflict began with a Prussian declaration of war on Denmark, and the country later expanded its war aims to annex the entire Jylland peninsula from Denmark. Mecklenburg entered the conflict and demanded the Schwelsig-Holstein region. Holstein entered the war in defense of its ally Denmark and became the site of the first fighting.